A chapter of bands that prove the boundaries of punk are porous; it’s less a genre than an animating spirit that allows for a lot of variation and weirdness. You can stretch a song out to King Crimson lengths and add a saxophone solo, and still be punk. You can play mostly acoustic instruments like the Violent Femmes, and still sound as angry and horny as any other punk band. You can play with structure like the Minutemen, or add lurching tempo shifts like Suicidal Tendencies does on the brilliant “Institutionalized.” You can even pretend to kill babies while singing like Elvis.